Infection is a common precipitant of DKA and HHS, and a history of an infective illness may be obtained. An appropriate history should also pick up any of the other precipitants for DKA or HHS listed in table 2, with particular attention paid to cardiac causes and omission of medication. The extreme metabolic disturbance of DKA can lead to laboratory and physical findings that may mislead the unwary and it is important to be aware of these pitfalls, which are summarised in box 2.